Self-Study vs. Classes

'Sup /lang/.

Which is better when learning a foreign language? Self-Study or classes? Which do you prefer?

I left school with a D in Spanish.

I've been studying Japanese for a few months, self-taught, and can so far flick through a manga (with furigana, of course) and get the general gist, and identify about 200 kanji prett fast. All of that came from the internet. Tae Kim + Jim Breen and a handy DS dictionary is basically all I need to learn it. And this guy I know who's studying it at school for almost 2 years knows less than me.

Now I really really want to learn Spanish and perhaps French too. I've picked up Spanish again, and can probably say that I've learned more useful phrases, words, etc in about 6 months than I did at school. For me, I didn't pay huge attention every single lesson, at least with self-teaching, you can do it whenever you want, and, more importantly, with the right motivation and the perfect pace.